internal -> emacs-mule, automatic-conversion -> undecided.
Coding category name changes as follows:
coding-category-internal -> coding-category-emacs-mule.
Delete functions describe-LANGUAGE-support.
Delete describe-function entries and change documentation
entries in each language specific information.
interactive and add new functions describe-LANGUAGE-support for
all LANGUAGEs supported. Remove resisterations of input methods
which use the function encoded-kbd-select-terminal.